Noon, on a dirt track in Helmand province, Afghanistan. A soldier sees something on the ground and kneels down for closer inspection. Mercifully, it is not an explosive device but a spider. The soldier screams and jumps back, despite it not being poisonous. If you saw this you would likely conclude that he has arachnophobia. A reporter would say the same. Though not a psychiatrist, you would deem yourself fit to label the soldier thus. But the world-famous news agency Associated Press (AP) yesterday deemed the attributing of other phobias – in particular homophobia and Islamophobia – inappropriate. Their new style guide warns reporters against using phobic terms in "political or social contexts".

"Homophobia especially – it's just off the mark. It's ascribing a mental disability to someone, and suggests a knowledge that we don't have. It seems inaccurate. Instead, we would use something more neutral: anti-gay, or some such … We want to be precise and accurate and neutral in our phrasing."

It is commendable to strive for accurate, neutral reporting and "homophobia" or "Islamophobia" are not ideal, as they denote solely the fear motivating prejudice. But they are the best we have. While fear may not be the only force behind such attitudes, it is invariably a chief component. AP's assertion that these words are inaccurate isn't remotely neutral or precise; it reveals a banquet of their own assumptions about what governs prejudice. It illustrates the chasm of understanding between an onlooker struggling to read a situation and a victim who, through jabbing repetition, comprehends it only too well.

I've spent 30 years understanding homophobia. When you can feel its breath on your face, spitting, threatening, bullying and abusing you, one tends to be rather more adept at analysing its motives than, say, the policeman who plods in with his or her notebook. Given this, I can report with a certainty rarely enjoyed by straight journalists that being anti-gay is, without exception, at least partly fuelled by fear. Fear of the unknown, fear of unwanted sexual attention, fear of gender roles being flouted, fear of humanity being wiped out by widespread bumming, fear of a plague of homosexuals dismantling marriage, the family, the church and any other institution held vaguely dear. And, of course, never forget: fear of what lurks repressed and unacknowledged in the homophobe. Irrational fear. It's a phobia, people.

Of course, those in the throes of this phobia are in denial. They never recognise it as such. Instead, they cling to their "deeply held convictions" that, for example, allowing people of the same sex to marry each other will ruin it for everyone else. They cling to their rosary beads or the backs of their trousers insisting it is a moral objection. But a glance at those objections unfailingly reveals an unwarranted belief that something bad will happen if you grant gay people the same rights as their heterosexual counterparts.

To shy away from describing this paranoia is to collude with it, to whitewash hate and prejudice. "Anti-gay" is fine just as "anti-Muslim" is, but "homophobia" and "Islamophobia" don't only offer exact synonyms, but deeper, richer ones. The Diagnostic and Statistical Manual IV – psychiatry's glossary of mental disorders – lists phobias of varying kinds, as well as other common conditions such as anxiety and depression. Should an AP reporter refrain from describing as anxious someone sweating and pacing up and down as they await execution?

Phobias are of course a spectrum. Someone who thinks that gay men might be too hedonistic to properly bring up a child is less phobic than someone who refuses to sit next to a Muslim because they are convinced anyone belonging to Islam is harbouring extremist tendencies. But they're all symptoms of an irrational, disproportionate fear: a phobia. To ban reporters – our eyes and ears around the world – from, say, describing the Ugandan MP David Bahati as homophobic (Bahati thinks the death penalty for gay people is necessary "to protect children") isn't merely censorious for the journalist. It blinds and deafens everyone else to what is really going on.